This is when a person wins, or does well at something. It is a combination of the name quinn, and the verb winning. Together they make the adjective Quinning. It originates from charlie sheen saying duh winning.

Chad-"Hey how did Quinn do in the boxing ring today?"
sylvester-"Come on... it's Quinn. Duh, He was Quinning"

"You need to vote Quinn for president; Didn't you know quinning is winning"